The present invention relates to a communication system which is able to carry out full duplex communication of a digital signal.
For the purpose of carrying out said two way digital signal communication, either a semiduplex communication system or a full duplex communication system are conventionally used. The former commonly utilizes a pair of wires for two way transmission, however it cannot undertake simultaneous two way communication since the flow of information is always one way. The latter can communicate two ways at the same time, for example, by frequency dividing a pair of wires and converting the digital signal into an amplitude-shift keying signal (ASK), a phase-shift keying signal (PSK), a frequency shift keying signal (FSK) or other similar techniques.
However, the above mentioned frequency divided full duplex communication system requires a modulation and a demodulation apparatus, and is best suited for large scale communications.
It would be economically inconvenient to utilize said system in small scale communications.